This invention relates to an ultrasonic diagnostic apparatus, and more specifically to an ultrasonic diagnostic apparatus for an endoscope.
Ultrasonic diagnostic apparatus for an endoscope are classified into two types; one for rigid endoscopes and the other for flexible endoscopes. The ultrasonic diagnostic apparatus for rigid endoscopes have an advantage in being able to provide more accurate positional (angular) information for scanning. As for the ultrasonic diagnostic apparatus for flexible endoscopes, they can vary slicing directions and provide closer contact with the surface of a subject. With the prior art ultrasonic apparatus for rigid endoscopes, however, it is hard to bring the distal insert section of a probe device closely into contact with the surface of the subject. Therefore, the probe device is ultrasonically brought into contact with the subject surface by using a balloon filled with a liquid or by filling the body cavity with the liquid. With these apparatus, moreover, the slicing direction cannot be widely changed, so that the range of diagnosis will be limited in some measure. With the ultrasonic diagnostic apparatus for flexible endoscopes, on the other hand, the scanning position (angle) cannot be accurately detected because of the flexibility of the scanning system although the slicing direction can be varied over a wide range.
It is therefore an object of this invention to provide an ultrasonic diagnostic apparatus for endscopes capable of closely touching the cavity wall of a patient body and setting the slicing direction over a wide range.